Captive bolt firearm and magazine therefor

ABSTRACT

A firearm of the captive bolt type as used for humane slaughtering of animals wherein a column of cartridges for firing the bolt are housed in a removable magazine, the breech block is rotatable to and from a firing position and on such rotation the cartridge at the head of the column is automatically loaded into the breech block.

ted States Patent 1191 i 1111 3,755,949

Hancox 1 Sept. 4, 1973 CAPTIVE :OLT FIREARM AND MAGAZINE FOREIGN PATENTS OR APPLICATIONS THEREFO 907,815 7/l945 France 42/l M [75] Inventor: Roger John Hancox, Burntwood,

England Pnmary ExammerBen am1n A. Borchelt [73] Assignee: Accles & Shelvoke Limited, Aston, Assistq rzt Ea'gmir lepg 7 England Att0rneySol0n B. Kemon, Carroll Palmer et al.

[22] Filed: Mar. 27, 1972 [21] Appl. No.: 238,492 [57] ABSTRACT A firearm of the captive bolt type as used for humane M slaughtering of animals wherein a column of cartridges llll- A22b for firing the bolt are housed in a removable magazine, [58] Field Of Search 42/1 M, 39.5; the breech block is rotatable to and from a firing posi- 17/ l 1 tion and on such rotation the cartridge at the head of the column is automatically loaded into the breech [56] References Cited block.

UNITED STATES PATENTS 3,068,601 12 1962 Arrowsmith 42 1 M 8 Chums 3 Draw; F'gures a e 2 e 76 Xi 75 V V 1 U8 6 2 9a A I 2932 7Q 30 PATENTEDSEP 41973 3155949 SHEET 2 F 2 76 1 5/ !26\ 1 n W x 23 7 21 f g I 22 CAPTIVE BOLT FIREARM AND MAGAZINE THEREFOR This invention relates to firearms for use in the humane slaughtering of animals of the captive bolt type, wherein a bolt accommodated within and coaxially of the barrel] of the firearm, is adapted to be driven lengthwise of the barrel by the explosive force applied thereto when a blank cartridge is fired in the breech block of the firearm.

Known firearms of this type have been so constructed that, before it is possible to fire any one of them, it is necessary to perform a sequence of time consuming, manual operations which includes opening a cartridge chamber in the breech block of the firearm and inserting a cartridge into and then re-closing the chamber. As a consequence, although automatic means have been provided for extracting the spent shell of the cartridge from the chamber during the performance of the next sequence of manual operations after the firearm has been fired, the number of the sequences of operations which may be performed in any unit of time, is limited. The principal object of the present invention is to overcome, or at least minimise, this disadvantage.

In accordance with the said invention, the breech block of a firearm of the captive bolt type is cylindrical, is rotatable about its axis, between a firing position and a cartridge extracting position, upon a concentric arcuate seating in the body of the firearm, and has a radial cartridge chamber opening to its periphery, and a passage which extends through the said body and opens to the seating in the path of travel of the open chamber end as the block is turned between the said positions, is adapted to receive a column of cartridges in end-toend abutment, and a spring which urges the column lengthwise of the passage towards the seating so that, each time the block is turned away from and back to the firing position, the cartridge at the head of the column may be transferred automatically from the passage into the chamber.

in order that the invention may be understood and carried into practice more readily, one typical embodiment thereof will now be described, by way of example, with reference to the accompanying drawing wherein:

FIG. 1 is an elevation, mainly in section, of a captive bolt pistol such as used in the humane slaughtering of animals;

FIG. 2- is a section along the line 11-11 of FIG. 1; and

FIG. 3 is a sectional elevation, on a larger scale, showing part of a magazine after removal from the pisto].

The pistol shown in FIGS. 1 and 2 comprises a body 1 which has a depending grip or stock 2 and an upwardly extending cylindrical housing 3. The grip 2 mounts a trigger 2a for actuating the firing mechanism through a plunger la seated in a bore in the body 1 in the known manner.

A unit which includes the barrel 4 and the breech block 5 of the pistol, is rotatable manually within the housing 3 about the axis of the barrel 4, and is held against axial displacement towards the muzzle 4a of the barrel by abutment of the breech block 5 against the rim of the adjacent end of the housing 3.

The breech block 5 is in peripheral contact with an arcuate seating 6 formed in the housing 3. The breech barrel axis and opens to the periphery of the block, and of which the other arm extends axially of the block and opens into the adjacent end of a co-axial expansion chamber 8 formed in the block and opening into the interior of the barrel. A piston 9 integral with a bolt 9a of the pistol, extends into and is a close sliding fit within the expansion chamber 8.

The barrel and block unit is rotatable between one extreme firing position in which the radial arm 7a of the cartridge chamber 7 is in axial alignment with the firing pin 10 of the pistol, and in opposite extremely cartridge-extracting position in which the said radial arm opens into a pocket 11 formed in the body laterally of the seating 6. A passage 12, of which the longitudinal centre line intersects the barrel axis is located in a plane common to the longitudinal centre lines of the radial arm 7a and the firing pin 10, opens to the seating 6 between the pin and the pocket 11. Consequently, as the unit is turned from one to the other of the said extreme positions, the mouth of the radial arm 7a traverses and registers momentarily with, the mouth of the passage 12.

Further, as the unit approaches the cartridgeextracting position, the mouth of the radial arm 7a travels beyond the seating 6 and opens into the pocket 11, and one end of an extractor rod 13 extending through and reciprocable in the breech block 5, contacts and travels along a cam surface 14 formed on the body 1 on the opposite side of the passage 12 to the pocket 11. The opposite end of the extractor rod 13 is provided with a foot 15 having, in its free end, an arcuate recess which is of the same radius as and coincides with an arc of the mouth of the radial arm 7a, and is adapted, when a blank cartridge 16 is fed into the chamber, to overhang the rim 17 of the cartridge. Consequently, as the rod 13 contacts and travels along the cam surface 14, the rod is displaced axially within the breech block 5 in the direction which drives the foot 15 outwardly of the block and extracts the cartridge 16 from the chamber 7.

A magazine comprising an outer tube 18 and an inner tube 19 is assembled within the passage 12. A knob 20 is socketted on and fixed to the end of the outer tube 18 remote from the seating 6, and is socketted into a bush 21 fixed within the adjacent end of the passage 12. The bush 21 is formed with a circumferential groove 22 which is engaged by circlip 23 mounted within the internal periphery of the bush 21 so as to retain the ma gazine within the passage 12 in a readily removable manner. if so desired, the magazine may be detachably assembled in the passage by any other analogous means; for example, the knob 20 may be threaded externally and the bush 21 may be threaded internally so that the magazine may be assembled in the passage by screwing the knob into the bush.

The inner tube 19 is a sliding fit within the outer tube 18, and the end remote from the seating 6 is closed by a plug 24 having a circumferential flange which projects beyond the external periphery of the inner tube. The opposite end of the inner tube 19 is formed with an external circumferential flange 25 which overhangs the rim of the adjacent end of the outer tube 18 and is trapped between the rim and an internal circumferential shoulder 26 formed in the passage 12. Between the shoulder 26 and the seating 6, the diameter of the passage 12 is equal to the diameter of the bore of the inner tube 19.

In addition, the inner tube 19 is urged inwardly of the outer tube 18 by a secondary compressed coil spring 27 which acts on the plug 24. A plunger 28, which is a sliding fit within the inner tube 19, is anchored to and is urged towards the seating 6 by a main compressed coil spring 29, and at least one ball 30 is located partly in a hole 31 in the wall of the inner tube and partly in an annular groove 32 in the internal surface of the outer tube.

The radial depth of the groove 32 is less than the diameter of the ball 30 by an amount which is equal to, or is substantially equal to but is not less than, the thickness of the wall of the inner tube 19 so that the .ball 30 is prevented from falling out of the hole into the groove 32 and, when in contact with the floor of the groove, does not protrude into the bore of the inner tube. The diameter of the hole 31 decreases from a maximum at its radially outer end, which is not less than the diameter of the ball, to a minimum at its inner radial end which is less than the said diameter so that the ball is able to protrude, but not fall, into the bore of the inner tube 19. An annular clearance 33 which extends from the groove 32 to the flange-abutting rim of the outer tube and of which the radial dimension, plus the thickness of the wall of the inner tube, is less than the ball diameter, is formed between the internal periphery of the outer tube 18 and the external periphery of the inner tube 19.

The distance between the hole 31 and the flange end of the inner tube 19, is less than the axial dimension of the clearance 32 so that when, as shown in FIGS. 1 and 2, the magazine is assembled in the passage 12, the ball 30 is located within and adapted to contact the floor of the groove and, consequently, the main spring 29 is able to drive the plunger 28 along the inner tube 19, past the ball 30 and beyond the shoulder 26, to the seating 6. However, upon removing the knob 20 from the bush 21 and withdrawing the magazine from the passage so that the flange 25 is retracted from the shoulder 26, the secondary spring 27 drives the inner tube 19 lengthwise of the outer tube 18 until the flange of the plug 24 abuts the rim of the adjacent end of the tube 19, and (see FIG. 3) the ball 30 is transferred from the groove 32 into the annular clearance 33 so that it is forced inwardly and protrudes into the bore of, the inner tube until it abuts the inner, smaller diameter, radial end of the hole 31.

Having withdrawn the magazine from the passage 12, the plunger 28 may, if necessary, be returned and a cartridge 16 may be inserted, rim foremost, into the flanged end of the inner tube 19. As the cartridge 16 is depressed manually inwardly of the tube, the plunger abuts the ball and the inner tube 19 is driven inwardly of the outer tube 18 until the ball re-enters the groove 31 so that the plunger 28 and then the rim 17 of the cartridge travel beyond the ball 30. Upon relieving the manual pressure applied to the cartridge 16, the inner tube 19 is again driven outwardly of the outer tube 18 by the secondary spring 27 and as the ball re-enters the clearance 33, it protrudes into the bore of the inner tube 19 so that it abuts the shell and overhangs the rim of the cartridge and prevents the latter being expelled from the inner tube by the main spring 29. By repeating the sequence of operations, additional cartridges may be inserted into the inner tube one after the other until, when the main spring has been compressed to its limit, the magazine has been fully loaded with a column of the cartridges and may be re-assembled in the passage 12.

As the magazine is being re-assembled in the passage, the flange 25 abuts the shoulder 26, the inner tube is driven inwardly of the outer tube, and the ball 30 is returned into the groove 32. As soon as the ball re-enters the groove, the main spring drives the column of cartridges outwardly of the inner tube until the cartridge at the head of the column reaches the seating 6 and contacts the periphery of the breech block 5.

Thereafter, upon turning the barrel and breech block unit from the firing position towards the cartridgeextracting position, the cartridge at the head of the column is transferred from the passage into the radial arm 7a of the cartridge chamber 7 and may be fired upon returning the unit to the firing position.

Subsequently, each time the unit is turned from the firing position to the cartridge-extending position, the spent cartridge is extracted from the cartridge chamber and, as the unit is returned to the former of the said positions, another of the cartridges is transferred to the radial arm 7a preparatory to being fired.

The magazine described above and shown in the drawings may be replaced by a magazine of any suit able alternative construction which is capable of being loaded with a column of the cartridges, of being detachably assembled in the passage 21 and, when so assembled, of transferring the cartridge at the head of the column into the radial arm of the cartridge chamber each time the barrel and breech block unit is turned manually from and back to the firing position.

For example, the magazine may comprise a single tube which has the knob 20, or an analogous knob, fixed upon one end, houses the main spring 29 and plunger 28, has at least one of the ball-engaged holes 21 formed in its wall in the vicinity of its opposite end, and is surrounded, again the vicinity of the said opposite end, by an internally grooved collar and the secondary spring; the collar and secondary spring may be located between two circlips each of which engages a corresponding one of two external circumferential grooves formed in and spaced apart lengthwise of the tube, one of th circlips being close to the tube end remote from the knob and the secondary spring being compressed between the collar and the other circlip so that it urges the collar along the tube towards the for-' mer of the two circlips.

To unload such a magazine with a column of the cartridges, it is withdrawn from the passage 12 whereupon the secondary spring drives the collar into abutment with the circlip remote from the knob and the groove in the collar is located between the ball and the said circlip so that the ball protrudes into the bore of the tube; then the collar is depressed manually against the action of the spring to locate the groove in radial register with the ball, and is held against spring-driven return movement whilst each cartridge is inserted into the tube and depresses the plunger against the action of the main spring; after the rim of the cartridge has travelled beyond the ball, first the manual pressure applied to the collar is removed so that the ball is driven into abutment with the shell of the cartridge, and then the manual pressure applied to the cartridge is removed so that the cartridge rim abuts the protruding ball and is prevented from being ejected from the tube by the main spring.

Having loaded the magazine with a column of cartridges, it is re-assembled in the passage and, during the re-assembly operation, the collar abuts and is depressed by the passage shoulder 26 to allow the cartridges to be transferred, one at a time, from the head of the colum as the barrel and breech block unit is turned from and back to the firing position.

Alternatively, the magazine may consist of a cylindrical pack of which the length is less than the distance between the shoulder 26 and the passage end remote from the seating 6, and each end is closed by a frangible diaphragm, and which is loaded with a column of the cartridges; after inserting such a magazine into the passage, the main spring is inserted and compressed manually and is maintained in its compressed condition by connecting a closure plug in the said passage end. As the spring is compressed, it drives the magazine along the passage until the pack abuts the shoulder 26 and then, ruptures the diaphragm in the adjacent end of the pack whereupon the spring pressure is applied to the column ruptures the other diaphragm so that the spring drives the column endwise within the pack until the cartridge at the head of the column abuts the periphery of the breech block and is positioned ready for transfer into the cartridge chamber. When all the cartridges have been transferred, the empty pack is removed from the passage and may be discarded as scrap.

I claim:

1. A firearm comprising a barrel accommodating a co-axial captive bolt for movement lengthwise of said barrel, a rotatable breech block receiving a blank cartridge and receiving a piston end of said captive bolt, means for firing said blank cartridge so that said captive bolt is moved lengthwise of said barrel in response to the explosive force of said firing, a body housing said firing means, an arcuate seating formed in said body and engaging with said rotatable breech block to permit rotation of said breech block between a firing position and a cartridge-extracting position, a radial cartridge chamber formed in said breech block and opening to said seating, a passage extending through said body opening to said seating and in the path of travel of said radial cartridge chamber when said breech block is rotated between said firing position and said cartridge-extracting position, a column of said blank cartridges received within said passage, and spring means urging said column towards said seating whereby each time said breech block is rotated between said firing position and said cartridge-extracting position, the blank cartridge at the head of said column is transferred from said passage into said radial cartridge chamber.

2. A firearm according to claim 1 wherein said column of blank cartridges are housed in a magazine and said spring means includes a compressed main coil spring accommodated in said passage and co-axial with said column, said main coil spring being located between said column and the end of said passage remote from said seating and acting on a blank cartridge at the foot of said column.

3. A firearm according to claim 2 wherein said magazine comprises an outer tube, an inner tube concentric with said outer tube and slidable within said outer tube, said column of blank cartridges and said main coil spring being contained within said inner tube, a plug fixed within the end of said inner tube remote from said seating, a secondary coil spring, engaging said plug to urge said inner tube towards said seating and a closure member fixed to the end of said outer tube remote from said seating retaining said secondary coil spring.

4. A firearm according to claim 3 wherein the ends of said inner and outer tubes adjacent said seating are provided with co-operating means for permitting insertion of said blank cartridges into said inner tube and for preventing ejection of said column of blank cartridges by said main coil spring when said magazine is removed from said passage.

5. A firearm according to claim 4 wherein said plug includes a projection abutting an internal shoulder of said outer tube to limit the lengthwise travel of said inner tube relative to said outer tube in response to the urge of said secondary spring.

6. A firearm according to claim 5 wherein said end of said inner tube adjacent said seating includes an external projection which overhangs the adjacent said end of said outer tube, and said passage includes an internal shoulder adjacent said seating abutting said external projection and arranged to engage with said adjacent end of said outer tube when said secondary spring is compressed.

7. A firearm according to claim 6 wherein said cooperating means comprises a ball engaged and partly located in a hole in said inner tube, an internal recess formed in said outer tube also partly locating said ball when said internal shoulder and said external projection are abutting, said ball being displaceable towards the bore of said inner tube on lengthwise movement of said inner tube relative to said outer tube caused by said secondary spring means.

8. A firearm comprising a barrel accommodatihg a co-axial captive bolt for movement lengthwise of said barrel, a rotatable breech block receiving a blank cartridge and receiving a piston end of said captive bolt, means for firing said blank cartridge so that said captive bolt is moved lengthwise of said barrel in response to the explosive force of said firing, a body housing said firing means, an arcuate seating formed in said body and engaging with said rotatable breech block to permit rotation of said breech block between a firing position and a cartridge-extracting position, a radial cartridge chamber formed in said breech block and opening to said seating, a passage extending through said body opening to said seating and in the path of travel of said radial cartridge chamber when said breech block is rotated between said firing position and said cartridge-extracting position, a column of said blank cartridges received within said passage, and spring means urging said column towards said seating whereby each time said breech block is rotated between said firing position and said cartridge-extracting position, the blank cartridge at the head of said column is transferred from said passage into said radial cartridge chamber, a magazine comprising a tube containing said column of blank cartridges, a compressed main coil spring constituting at least part of said tube, a detachable closure member in said end of said passageway remote from said seating and closing the adjacent end of said tube, and co-operating means for permitting insertion of said blank cartridges into said inner tube and for preventing ejection of said column of blank cartridges by said main coil spring when said magazine is removed from said passage.

t t k =3 

1. A firearm comprising a barrel accommodating a co-axial captive bolt for movement lengthwise of said barrel, a rotatable breech block receiving a blank cartridge and receiving a piston end of said captive bolt, means for firing said blank cartridge so that said captive bolt is moved lengthwise of said barrel in response to the explosive force of said firing, a body housing said firing means, an arcuate seating formed in said body and engaging with said rotatable breech block to permit rotation of said breech block between a firing position and a cartridgeextracting position, a radial cartridge chamber formed in said breech block and opening to said seating, a passage extending through said body opening to said seating and in the path of travel of said radial cartridge chamber when said breech block is rotated between said firing position and said cartridgeextracting position, a column of said blank cartridges received within said passage, and spring means urging said column towards said seating whereby each time said breech block is rotated between said firing position and said cartridge-extracting position, the blank cartridge at the head of said column is transferred from said passage into said radial cartridge chamber.
 2. A firearm according to claim 1 wherein said column of blank cartridges are housed in a magazine and said spring means includes a compressed main coil spring accommodated in said passage and co-axial with said column, said main coil spring being located between said column and the end of said passage remote from said seating and acting on a blank cartridge at the foot of said column.
 3. A firearm according to claim 2 wherein said magazine comprises an outer tube, an inner tube concentric with said outer tube and slidable within said outer tube, said column of blank cartridges and said main coil spring being contained within said inner tube, a plug fixed within the end of said inner tube remote from said seating, a secondary coil spring, engaging said plug to urge said inner tube towards said seating and a closure member fixed to the end of said outer tube remote from said seating retaining said secondary coil spring.
 4. A firearm according to claim 3 wherein the ends of said inner and outer tubes adjacent said seating are provided with co-operating means for permitting insertion of said blank cartridges into said inner tube and for preventing ejection of said column of blank cartridges by said main coil spring when said magazine is removed from said passage.
 5. A firearm according to claim 4 wherein said plug includes a projection abutting an internal shoulder of said outer tube to limit the lengthwise travel of said inner tube relative to said outer tube in response to the urge of said secondary spring.
 6. A firearm according to claim 5 wherein said end of said inner tube adjacent said seating includes an external projection which overhangs the adjacent said end of said outer tube, and said passage includes an internal shoulder adjacent said seating abutting said external projection and arranged to engage with said adjacent end of said outer tube when said secondary spring is compressed.
 7. A firearm according to claim 6 wherein said co-operating means comprises a ball engaged and partly located in a hole in said inner tube, an internal recess formed in said outer tube also partly locating said ball when said internal shoulder and said external projection are abutting, said ball being displaceable towards the bore of said inner tube on lengthwise movement of said inner tube relative to said outer tube caused by said secondary spring means.
 8. A firearm comprising a barrel accommodatihg a co-axial captive bolt for movement lengthwise of said barrel, a rotatable breech block receiving a blank cartridge and receiving a piston end of said captive bolt, means for firing said blank cartridge so that said captive bolt is moved lengthwise of said barrel in response to the explosive force of said firing, a body housing said firing means, an arcuate seating formed in said body and engaging with said rotatable breech block to permit rotation of said breech block between a firing position and a cartridge-extracting position, a radial cartridge chamber formed in said breech block and opening to said seating, a passage extending through said body opening to said seating and in the path of travel of said radial cartridge chamber when said breech block is rotated between said firing position and said cartridge-extracting position, a column of said blank cartridges received within said passage, and spring means urging said column towards said seating whereby each time said breech block is rotated between said firing position and said cartridge-extracting position, the blank cartridge at the head of said column is transferred from said passage into said radial cartridge chamber, a magazine comprising a tube containing said column of blank cartridges, a compressed main coil spring constituting at least part of said tube, a detachable closure member in said end of said passageway remote from said seating and closing the adjacent end of said tube, and co-operating means for permitting insertion of said blank cartridges into said inner tube and for preventing ejection of said column of blank cartridges by said main coil spring when said magazine is removed from said passage. 